When utilizing metal oxide semiconductor field effect transistors (MOS-FETs) it is general knowledge that as amplifiers, they are limited to small signal situations. It is also known that, when they are structured as depletion type devices, their ability to amplify incoming signals is not restricted to the reversed biased range of their gate to source voltage handling limitations; indeed, they will tolerate temporary excursions into the forward biased range of the handling limitation without degrading the impedance between the gate and source.
This characteristic makes possible a zero-biased arrangement of the MOS-FETs for signal amplification. It is also possible to structure the MOS-FETs in a push-pull arrangement so that their performance potentional can be maximized in light of the latest technological developments for manufacturing said devices.
The fact that the transconductance of MOS-FET transistors increase proportionally to the onresistance, would make it desirable to structure the channel's cross-sectional dimensions as small as possible. The recent application of lasers in the manufacturing of such devices can reduce the channel dimensions to much less than one micron, with a high degree of consistency in maintaining the dimensions.
It is an object of the invention to utilize MOS-FETs manufactured by laser technology to their maximum potential in various circuit arrangements. Such circuit arrangements permit a large increase in transistor performance, the increased performance being a result of the circuit's ability to process an incoming signal despite the internal noise inherent in small signal amplifiers.
One possible use of such circuitry is in an FM demodulator when a de-emphasis circuit is included. Such circuitry may also be used as a radar or sonar demodulator including automatic frequency control and squelch circuits, but without the need for de-emphasis and limiting circuits.
It is the intent of this disclosure to bring to general knowledge a completely symmetrical discriminator and demodulator circuit.
It is a further intent of this disclosure to bring to general knowledge a completely symmetrical discriminator and demodulator circuit which includes an extremely sensitive and symmetrical limiter or squelcher.
It is a still further intent of this disclosure to bring to general knowledge a completely symmetrical discriminator and demodulator circuit which includes automatic frequency control.
It is an even further intent of this disclosure to bring to general knowledge a completely symmetrical discriminator and demodulator circuit which includes a symmetrical first stage analog amplifier and a volume control. It is yet another intent of this disclosure to bring to general knowledge a complete symmetrical discriminator and demodulator circuit which includes a symmetrical de-emphasizing function when utilized as an FM demodulator.